PHILADELPHIA -- Boston Celtics coach Doc Rivers said Mickael Pietrus will spend the night in Philadelphia after suffering a questionable closed head injury (concussion) during Friday's 99-86 loss to the 76ers at Wells Fargo Arena.

Reading from a piece of paper after the team's medical staff gave him an update, Rivers said Pietrus had undergone an X-ray and a CT scan at a Philadelphia-area hospital. Pietrus was also scheduled for an MRI Friday night, but the team said he will not be admitted to the hospital. Pietrus will spend the night in Philadelphia and be re-evaluated on Saturday.

Rivers admitted it was a frightening scene on the court.

"It looked awful," Rivers said. "I saw it immediately -- I didn't think he hit his head, I wasn't sure, but I just saw his neck snap, so you knew that was bad. Obviously, he was throwing up on the floor, so that wasn't very good, either."

A closed head injury, according to the Brain and Spinal Cord website, is "a trauma in which the brain is injured as a result of a blow to the head, or a sudden, violent motion that causes the brain to knock against the skull. A closed head injury is different from an open head injury, in that no object actually penetrates the brain.

"Closed head injuries can be diffuse, meaning that they affect cells and tissues throughout the brain; or focal, meaning that the damage occurs in one area. Closed head injuries can range from mild to severe."

For a Celtics team that has lost two players to heart ailments (Jeff Green, Chris Wilcox) and another to a season-ending wrist injury (Jermaine O'Neal), the injury is the latest blow to its never-ending health woes.

"It's just been a hell of a year right now," Rivers said.

Already reeling from the frightening injury scare with Pietrus, the Celtics also lost the services of Avery Bradley to a sprained left ankle.

Bradley appeared to tweak the ankle late in the first half and departed with 41.1 seconds to play in the second quarter. With Ray Allen out due to his own ankle ailment, the Celtics were left depleted at the guard spot.

Rivers applauded his team's resiliency, even after Friday's game slipped away.

"We have a resilient group, though," Rivers said. "I'm so proud of our team -- we just keep sustaining injuries. But guys are just trying to play and win. That's really nice. ...

"It's maddening, but it is what it is. We are passing the test. That's all we can do. It's just tough. Every night it seems like -- what's amazing is it has nothing to do with age; it's the young guys. Things happen. But I keep telling them, we've decided to be that grind team; we gotta keep doing that."

"It's always tough when you see your fellow NBA player, regardless of who it is," go down, Pierce said. "When you see someone laying there on the ground, not moving and getting carried off the floor on a stretcher -- it's tough. In any sport; I'm a sports fan and whenever you see that, you feel for the person, feel for their families. Those (injuries) can be career-ending type of things, and you see it all the time. We just hope that he's able to make it through these things."

Marquis Daniels endured a frighteningly similar scene last year suffering a freak spine injury that ended his season in a game against the Orlando Magic at TD Garden.

Daniels required offseason surgery for a lifelong spine condition. He admitted the situations are different, but seeing Pietrus carted off certainly resonated for him.

"I just started praying immediately," Daniels said. "You never like to see anybody down like that, let alone your teammate. It's kind of a tough moment, but he's a tough guy. He's going to pull through."